Many problems in materials processing require the use of a high power laser (or similar light source) which could have a variety of problems. Some of these problems could be a multimode beam structure that may be irreproducible from pulse to pulse or in long term operation and/or a low temporal coherence and/or a low spatial coherence and/or a bad beam pointing stability. Therefore because of these difficulties in achieving a reliable I(x,y,z,t), where I is intensity, t is the time coordinate and x,y,z are arbitrary space coordinates, it is difficult in general to use certain lasers to simultaneously process an entire area even when the energy of the laser beam is high enough. The object of the invention is to provide a method of getting reproducible, stable, and reliable energy profiles on a desired surface on which the material to be processed is placed. In general material processing by light does not depend on the phase of the beam profile, i.e. its spatial coherence and thus, our invention is restricted to those cases in which the phases of the I(x,y,z) are not a relevant factor.
To meet the requirements for an appropriate I(x,y,z) distribution we apply a combination of technologies based on geometrical optical and physical optical principles.